Reactive Chemistry
Chemical Reactions
What are the products of a chemical reaction?
1 investigate a variety of reactions to identify possible indicators of a chemical change
Chemical Change- Common Signs:
Micro: rearrangement of atoms or new substances formed
Macro:
- Gas is produced
- Solid precipitate produces
- Change in colour
- Change in temperature (significant)
- Solid disappears
- Odour produced
2 use modelling to demonstrate
- the rearrangement of atoms to form new substances
- the conservation of atoms in a chemical reaction
Ball and Stick model:
1. Chemical change and reactions involve the rearrangement of atoms
2. Adherence to the law of conservation of energy
https://learn.getatomi.com/subscriptions/17000/classes/1285648/modules/3350/posts/339
5
3 conduct investigations to predict and identify the products of a range of reactions, for example:
- synthesis
- decomposition
- combustion
- precipitation
- acid/base reactions
- acid/carbonate reactions
Synthesis Reaction
Definition: combination of multiple reactants to form a single product (e.g. the formation of water
from hydrogen and oxygen)
- The formation of new bonds releases energy making them exothermic
,Predicting The Product:
- Non-metals in the top right will react with most metals to form ionic compounds
- Metals do not react chemically with other metals
- Non metals often react with other non metals to form covalent compounds (e.g. halogens
reach with hydrogen to form hydrogen halides)
Decomposition Reaction
Definition: A single compound decomposing into two or more elements or compounds (e.g. the
breaking of water to hydrogen and oxygen using electrolysis)
- Required energy to break bonds making them endothermic
Types Of Decomposition Reactions:
- Thermal Decomposition (heating)
➔ Easily decomposes hydroxides (oxides and water), most carbonates (oxide+
carbon dioxides), nitrates (oxides, nitrogen dioxide, oxygen)
➔ E.g. 𝐶𝑎𝐶𝑂3(𝑠)→𝐶𝑎𝑂 (𝑠) + 𝐶𝑂2 (𝑔)
- Electrolysis (electric current through them in the molten state or in solution)
➔ Electrolysis of water
- Decomposition By Light (exposure to light)
➔ Some pure substances can be decomposed by solids
➔ E.g. sunlight decomposes silver chloride into a black solid
2𝐴𝑔𝐶𝑙 (𝑠)→2𝐴𝑔 (𝑠) + 𝐶𝑙2 (𝑔)
Combustion Reaction
, Definition: the burning of elements or compounds in oxygen, at a temperature well above room
temperature (e.g. the burning of methane and octane)
- Produce energy- Exothermic
Precipitation Reaction
Definition: involve the formation of a precipitate (insoluble salt) from two aqueous solutions
- Can be either endo or exothermic
1. Two aqueous salts reacting together in a double replacement reaction with the cations and
anions switching partners
2. SNAPP solubility ruled to tell which is soluble or insoluble
Acid Base Reaction (Neutralisation Reactions)
Chemical Reactions
What are the products of a chemical reaction?
1 investigate a variety of reactions to identify possible indicators of a chemical change
Chemical Change- Common Signs:
Micro: rearrangement of atoms or new substances formed
Macro:
- Gas is produced
- Solid precipitate produces
- Change in colour
- Change in temperature (significant)
- Solid disappears
- Odour produced
2 use modelling to demonstrate
- the rearrangement of atoms to form new substances
- the conservation of atoms in a chemical reaction
Ball and Stick model:
1. Chemical change and reactions involve the rearrangement of atoms
2. Adherence to the law of conservation of energy
https://learn.getatomi.com/subscriptions/17000/classes/1285648/modules/3350/posts/339
5
3 conduct investigations to predict and identify the products of a range of reactions, for example:
- synthesis
- decomposition
- combustion
- precipitation
- acid/base reactions
- acid/carbonate reactions
Synthesis Reaction
Definition: combination of multiple reactants to form a single product (e.g. the formation of water
from hydrogen and oxygen)
- The formation of new bonds releases energy making them exothermic
,Predicting The Product:
- Non-metals in the top right will react with most metals to form ionic compounds
- Metals do not react chemically with other metals
- Non metals often react with other non metals to form covalent compounds (e.g. halogens
reach with hydrogen to form hydrogen halides)
Decomposition Reaction
Definition: A single compound decomposing into two or more elements or compounds (e.g. the
breaking of water to hydrogen and oxygen using electrolysis)
- Required energy to break bonds making them endothermic
Types Of Decomposition Reactions:
- Thermal Decomposition (heating)
➔ Easily decomposes hydroxides (oxides and water), most carbonates (oxide+
carbon dioxides), nitrates (oxides, nitrogen dioxide, oxygen)
➔ E.g. 𝐶𝑎𝐶𝑂3(𝑠)→𝐶𝑎𝑂 (𝑠) + 𝐶𝑂2 (𝑔)
- Electrolysis (electric current through them in the molten state or in solution)
➔ Electrolysis of water
- Decomposition By Light (exposure to light)
➔ Some pure substances can be decomposed by solids
➔ E.g. sunlight decomposes silver chloride into a black solid
2𝐴𝑔𝐶𝑙 (𝑠)→2𝐴𝑔 (𝑠) + 𝐶𝑙2 (𝑔)
Combustion Reaction
, Definition: the burning of elements or compounds in oxygen, at a temperature well above room
temperature (e.g. the burning of methane and octane)
- Produce energy- Exothermic
Precipitation Reaction
Definition: involve the formation of a precipitate (insoluble salt) from two aqueous solutions
- Can be either endo or exothermic
1. Two aqueous salts reacting together in a double replacement reaction with the cations and
anions switching partners
2. SNAPP solubility ruled to tell which is soluble or insoluble
Acid Base Reaction (Neutralisation Reactions)
